This invention relates to rechargeable batteries and more particularly to a simple, inexpensive, charging system whereby a rechargeable battery of the 9 volt physical size and/or electrical characteristics is selectively and alternatively connectible to a charge current source for recharging of the type described in U.S. Pat. No. 4,009,429.
There is an increasing number of consumer products being operated by rechargeable cells such as nickel-cadmium cells. These products require cells with a plurality of physical sizes and electrical characteristics. The variety of cell types in wide use in the consumer market has given rise to the need to provide a unitary charging device to accommodate the various cell types. One such device is described in U.S. Pat. No. 3,579,075 issued on May 18, 1971 and assigned to the assignee of the invention herein. While this device provides a viable approach for charging cells of a variety of types, it has failed to achieve widespread adoption in the consumer market because of its complexity and cost of construction. The system described in the above-identified U.S. Pat. No. 4,009,429 is useful in charging AA, C & D size batteries, but does not accept 9 volt size batteries. Commonly assigned application Ser. No. 877,297 discloses an improved system for 9 volt rechargeable batteries with the use of an adapter. Commonly assigned application Ser. No. 878,453 utilizes in combination a charger and 9 volt size battery which are interconnected by an adapter module. The adapter is designed to mechanically and electrically join the battery to the charger so that a highly compact system results. Electrical means such as diodes and resistors are carried by the adapter to transform the charger characteristics to those useful for the 9 volt battery. Thus, the usefulness of the charger is expanded to include 9 volt size batteries. The adapter in Ser. No. 878,453 is a single molded housing having two folded portions interconnected by a hinge and ultrasonically bonded by means of integral energy concentrators.